<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title>bg-color的开始渲染位置, 是从border-box开始渲染的</title>
	<style type="text/css">
		.boxs{
			text-align: center;
		}
		.box{
			display: inline-block;
			height:200px;
			width:200px;
			margin-right:20px;
			padding: 20px;
			border:10px dashed red;
			background-color: blue;
		}
	</style>
</head>
<body>
	<div class="boxs">
		<div class="box"></div>
	</div>
</body>
</html>